LUSAS User Area
Typical message given by LUSAS Modeller on attempting to
start- up or load/ manipulate a large file:
Memory request for ###MB failed (##MB available)
Insufficient virtual memory to run Modeller
Most common causes & links to solutions
This message is caused by a lack of space available for the
virtual memory ("Windows swap/ page file") on your PC.
You may have encountered a message similar to the following:
This message will appear if
Modeller requires more memory and a memory request fails. It tells
you how much memory was requested, how much is available, how much
Modeller is already using and what the limit is for your PC and
its current settings. In
this case the PC allows a maximum of 3071.9MB. By default, 32bit
Windows allows 2GB by default.
There are several reasons why your PC may run out of space for
virtual memory, these are listed with suitable solutions below:
Model problems may cause files to become
larger than necessary
-
Eliminate
modelling problems which trigger warnings in the text
output pane
-
Check
mesh refinement
(reduce number of elements or interpolation
order if appropriate)
PC settings may cause temporary files to clash
with virtual memory, or disk is full
-
Relocate
or expand PC virtual memory
-
Relocate
LUSAS temporary files
-
Relocate
Windows temporary files
-
Clear
temporary files
Modeller memory allocation settings may need
adjustment
-
Optimise
LUSAS memory usage - Release memory reserved for
post-processing to give more memory to pre-processing tasks
such as meshing or tabulating a Datafile.
PC hardware is inadequate for the size of
problem
-
Upgrade
PC hardware
More on cause & theory links
The operating system swap/ page
file is used by LUSAS Modeller and expanded automatically. For some LUSAS
models, the virtual memory requirements can be quite
significant such that all free space on the disk or partition to
which the swap/page file is currently being written (typically
the C:\ drive on a PC) may become exhausted. In order to
understand the cause of this error more fully, you may wish to
read the following theory pages:
More on how LUSAS uses PC
resources
LUSAS uses Windows temporary files and produces LUSAS
temporary files. In large models, these files can be of
significant size and they may take up
space on the disk, limiting space available for the operating system
swap/ page
file. Solutions relevant to this particular problem are
among those listed above.
This message can also occur because the
normal maximum amount of memory (RAM plus pagefile) that can be accessed (or addressed) by
a single application for 32 bit Windows is 2Gb and the
model requirements are greater than this. For some 32bit
versions of Windows the boot settings may be adjusted to increase
this limit to 3GB. If LUSAS is run on a 64bit operating system
it will be able to use up to 4GB of memory run in 32bit emulation.
As a 32bit application, LUSAS cannot use any more than this. A 64bit
version of Modeller is available for post-processing 64bit Solver
runs, or for mesh only modelling where the geometry of a model and
the meshing has been performed outside of LUSAS and the mesh in
imported into Modeller. A 64bit version of LUSAS Modeller for
geometry based modelling is under development.
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